There are three possible responses to this:
1. Get as organized and dedicated as the left-wingers editing the pages are and fight back.
2. Shrug it off and pick other battles to fight.
3. Piss, moan, and generally take your ball and go home, resulting in embarrassments like Conservapedia.
1. That would be hard. There are a lot of them, they’re well organized and fanatical, and they have a lot of time on their hands.
2. That would be self-defeating. Like surrendering Hawaii to the Japanese in World War II. WP is the premier info source on the Internet. Every Google search turns up a WP article as the first or second hit.
3. That would be both stupid and self-defeating.